package com.gitee.gateway.core.utils;

import org.apache.commons.codec.digest.DigestUtils;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import java.security.SecureRandom;

/**
 * 加解密工具类
 */
public class CryptUtils {

    private final static String DES = "DES";

    public static String generatePwd(long id, String pwd) {
        return DigestUtils.sha256Hex(id + "_" + pwd);
    }

    /**
     * 加密
     *
     * @param src 数据源
     * @param key 密钥，长度必须是8的倍数
     * @return 返回加密后的数据
     */
    public static byte[] encrypt(byte[] src, byte[] key) throws RuntimeException {
        try {
            // DES算法要求有一个可信任的随机数源
            SecureRandom sr = new SecureRandom();
            // 从原始密匙数据创建DESKeySpec对象
            DESKeySpec dks = new DESKeySpec(key);
            // 创建一个密匙工厂，然后用它把DESKeySpec转换成
            // 一个SecretKey对象
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
            SecretKey secureKey = keyFactory.generateSecret(dks);
            // Cipher对象实际完成加密操作
            Cipher cipher = Cipher.getInstance(DES);
            // 用密匙初始化Cipher对象
            cipher.init(Cipher.ENCRYPT_MODE, secureKey, sr);
            // 现在，获取数据并加密
            // 正式执行加密操作
            return cipher.doFinal(src);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * 解密
     *
     * @param src 数据源
     * @param key 密钥，长度必须是8的倍数
     * @return 返回解密后的原始数据
     */
    public static byte[] decrypt(byte[] src, byte[] key) throws RuntimeException {
        try {
            // DES算法要求有一个可信任的随机数源
            SecureRandom sr = new SecureRandom();
            // 从原始密匙数据创建一个DESKeySpec对象
            DESKeySpec dks = new DESKeySpec(key);
            // 创建一个密匙工厂，然后用它把DESKeySpec对象转换成
            // 一个SecretKey对象
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
            SecretKey secureKey = keyFactory.generateSecret(dks);
            // Cipher对象实际完成解密操作
            Cipher cipher = Cipher.getInstance(DES);
            // 用密匙初始化Cipher对象
            cipher.init(Cipher.DECRYPT_MODE, secureKey, sr);
            // 现在，获取数据并解密
            // 正式执行解密操作
            return cipher.doFinal(src);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * 数据解密
     *
     * @param data 待解密数据
     * @param key  密钥
     * @return 返回解密后的数据
     */
    public static String decrypt(String data, String key) {
        return new String(decrypt(hex2byte(data.getBytes()), key.getBytes()));
    }

    /**
     * 数据加密
     *
     * @param data 待加密数据
     * @param key  密钥
     * @return 返回加密后的数据
     */
    public static String encrypt(String data, String key) {
        if (data != null)
            try {
                return byte2hex(encrypt(data.getBytes(), key.getBytes()));
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        return null;
    }


    /**
     * 二行制转字符串
     *
     * @param b 二进制数组
     */
    private static String byte2hex(byte[] b) {
        StringBuilder hs = new StringBuilder();
        String stmp;
        for (int n = 0; b != null && n < b.length; n++) {
            stmp = Integer.toHexString(b[n] & 0XFF);
            if (stmp.length() == 1)
                hs.append('0');
            hs.append(stmp);
        }
        return hs.toString().toUpperCase();
    }

    private static byte[] hex2byte(byte[] b) {
        if ((b.length % 2) != 0)
            throw new IllegalArgumentException();
        byte[] b2 = new byte[b.length / 2];
        for (int n = 0; n < b.length; n += 2) {
            String item = new String(b, n, 2);
            b2[n / 2] = (byte) Integer.parseInt(item, 16);
        }
        return b2;
    }

    public static void main(String[] args) {
        if (args.length != 2) {
            System.out.println("Usage: passwd.sh [-e|-d] [password]");
            System.exit(1);
        }
        String key = "@GiteeGW#202309"; // must equals to DatabaseManager#PASSWORD_ENCRYPTION_SECRET_KEY
        boolean encrypt = "-e".equals(args[0]);
        if (encrypt) {
            System.out.printf("%s => %s\n", args[1], encrypt(args[1], key));
        } else {
            System.out.printf("%s => %s\n", args[1], decrypt(args[1], key));
        }
    }

}
